Air cooler



Nov. 2, 1937.

R. wENzL 2,0975851 AIR cooLER Y Filed April 22. 1935 @View 2 sheets-snee@ 1 Nv. Z, 1937. R.' wENzl. 2,097,851

AIR COOLER Fim April 22, '1955 2 sheets-sheet a,

Patented Nov. 2, 1(937 Richard wenn, Freiburg, Gex-mamy Application April 22, 193s, sex-n1 no. 17,707 In Germany April 26, 1934 6 Claims.

fecting the lowering of temperature in rooms, public buildings, etc., in storage rooms, such as the cellars of breweries, rooms where perishable goods are kept, in short, wherever a lowering of the temperature is desirable.

It is an object of my invention to provide a cooler by which the air in the room etc. is cooled to a low temperature by an eihcient refrigerant, such as brine, or a cooling gas, but in which, notwithstanding the Vfact that the temperature at the outer surfaces of its cooling elements must never be higher than 0, frosting is kept within such limits as not to give trouble, without uneconomic power demand or oversizing of the cooler. v

To this end, I provide, in an air cooler, a cooling unit with at cooling elements therein. Each element has a pair of parallel iiat walls and the elements are so arranged that they define air ducts by the outer surfaces of their parallel flat walls. Means are provided for circulating an elcient refrigerant through the cooling elements at such a temperature that the outer surfaces of the ductdening walls are maintained below 0, and a -fiow of air through the ducts is established at comparatively high velocity.

By suitably selecting the temperature oi the refrigerant, and imparting a proportionately high velocity to the air-which velocity should be higher than i3 ft. per secondfrosting is not prevented but kept within reasonble limits. At the same time, the airis cooled to a temperature below 0.

The problem underlying the present invention is to cool air to such low temperatures by'a cooler which is similar to the heat exchangers used for cooling air to temperatures not below 5 above zero.

The cooling elements of my cooler are at cells with two parallel flat side walls, and the `walls have plain outer surfaces, without ribs or other outwardly extending projections. Baines are arranged within the elements between their walls, for conducting the refrigerant through the elements in a zig-zag path. With such flat elements, or cells, and with a properly determined ratio of the refrigerant temperature and the velocity at which the air flows in the ducts between the elements, as described above, the. eiliciency of the cooler is increased, and its size is reduced, as compared with the existing cooling plants. A

cooler according to my invention is simpler and cheaper than such plants.

The simplicity of the parts constituting the ele- (Cl. 257-244) My invention relates to air coolers for eil-- ments, and the ease with which they are manufactured, facilitate4 quantity production of' standardized parts.

The elements, when combined into a cooling unit, present a very large cooling surface in a comparatively small unit. The efficiency is very high, on account of the high circulating velocity of the refrigerant, and the high ow Velocity of the air.

Frosting is not eliminated, as mentioned, but the flat and uniform surfaces of the elements forming the air ducts and the uniform lowering of the temperature, do not favor the local thickening of the frost into lumps which clog the ducts, and defrosting of the elements is rapid and uniform. By providing elements as described, it is `possible to depart from the present system of centralizathe mechanical eiiiciency at which the air is moved through the cooler. To this end, I provide streamlined portions-at the sides of the elements which extend transversely to the how of the air in the ducts. Such streamlined portions are preferably formed by folding the walls of the elements down upon each other at the sides, and connecting them by welding.

It is still another object of my invention to reduce the resistance opposed to the flow of the air at the inlet and outlet of the ducts. To this end, I provide bars for holding the elements, and connect the elements to the bars by brackets which are preferably placed outside the ow of the in- 'streaming and outstreaming air. The bars themselves are preferably streamlined.

In the accompanying drawings, a cooler embodying my invention is illustrated more or less diagrammatically' by way of example.

Vlin the drawings:

F18. 1 is a .vertical section ofva cooler whose nat cooling elements are equipped with welded-in baiiles,

rig. 2 is ai section on the une n-n in Fig. 1,

Fig. 3 is a section on the line III-HI in Fig. 1,

Fig. 4 is a section on the line IV--IV in Fig. 1, showing the streamlined lower side of an element on a larger scale,

Figs. 5 and 6 are sections similar to Fig; 4 but showing modied elements,

Fig. 7 is a vertical section, and i is an 55 elevation, of a modified element whose baflles are formed by inwardly projecting ribs.

Referring now to the drawings, and rst to Figs.` 1 to 3, the nat elements I are combined into a cooling unit which is housed in a casing 2, of sheet metal or the like. The end edges I0, and the side edges II, of the elements I lare spaced from the corresponding portions of fthe casing 2, and the Yelements are held at their upper and lower side edges II by bars I4 in suitable frames I9 and 20 at the bottom and top of the casing 2. The individual elements are connected to their bars I4 by brackets 2l. 'In the example illustrated, two brackets 2l are secured to the upper, and two more brackets 2| are secured to the lower edge II of each element, as shown in Fig. 1, and placed out of the way of the instreaming and outstreamlng air.

The bars I4 may be of plain rectangular cross section, as shown in Fig. 4, but are preferably streamlined, as shown in Fig. 5. Fig. 6 illustrates a bar I4' of channel section between whose flanges the element I is held.

Each element has a pair of parallel walls 8 and 9 which are folded down upon each other at the upper and lower sides of the element and preferably connected by welding, as shown for the lower side of an element in Figs. 4, 5, and 6. The ends I0 of the elements may be connected in a similar manner, as shown in Fig.'3.

Baffies I3 are inserted between the walls 8 and 9 of each element, and alternately connected to, and spaced from, the sides of the element. The baiiles I3 are preferably welded to the walls, as, shown in Fig. 4. One side of the baille, in the example illustrated, that side which bears against the wall 9, is connected to the wall by two welds 22 and 23. at the upper and lower face of the baille I3, and a fillet 24 in a slot, or fillets in holes, of the other wall 8, connect that wall to the corresponding side of the baille. The fillets 24 are constructed as follows:

The batiies are first welded to the inner side of the wall 9 by meansA of the two welds 22 and 23 (Fig. 4). In the side wall 8 before the cell is assembled there are bored a number of holes at suitable places and then the two walls 8 and 9 are brought together and secured int -such a way that the holes in the Wall 8, which latter form the llets 24, will each be. provided in the middle of one of the baiiies. 'Ihen the holes are lledup by electric welding to form each fillet 24 and thus the fillet will be welded to its baffle and to the material ofthe wall 8. The outer surface of the fillet 24 while still red hot isA hammered flat and eventually any surplus metal is ground off in order that the outer surface of the wall '8 shall be perfectly smooth. Thus in view of the manner in which this fillet 24 is formed it is quite evident that atight connection is made and therefore no leaks in the wall 8 will occur.

Refrigerant is circulated throughthe elements and between the baflles I3 by means'of an inow header 4, and an outflow header 5. The inflow header 4 is connected to the upper portion of each element by pipes 6 with flanges 25, and lto the lower portion of each element the outow header is connected by pipes 1 with anges 26, so that the refrigerant flows as indicated by the arrows I1 in Fig. 1.

The casing 2 of the cooler unit is secured to a tubular base 2l by angle sections 28. 'I'he lower end of the base 2l opens into a suction pipe 29 in .which an adjustable damper 30 is mounted on a suitable shaft 3 I, and turned by means of a handle 32 on one of its projecting ends.

- A fan chamber 33 is placed on top of the unit casing and connected to the casing by angle sections 34. A duct 35 is inserted in the front end wall of chamber 33, ,and a fan 3, rotated by a motor 36 on a suitable bracket 31, rotates in the duct 35 to draw air from suction pipe 29 (whose f ree sectional area is regulated by the damper 30) through the ducts between the elements I, and to discharge it through duct 35.

A spray pipe I5, with perforations I6, is placed across the lower portion of the fan chamber 33 for defrosting the elements I by water issuing from the perforations I6.

In operation, a low-temperatured refrigerant, for instance, brine, is circulated through the elements I and deected by the baffles, so that it flows through the elements at a suitable velocity. The walls 8 and 9 of the elements I are cooled to temperatures below 0 and a correspondingly low cooling of the air flowing in the ducts between the elements is effected. As mentioned, the flowing velocity of the air should be .comparatively high in order to prevent excessive frosting and clogging of the ducts., The now of the air to, through, and from,- the ducts between the elements I, and out of the casing, is as free from obstructions as practicable, and those members which necessarily obstruct the flow, are of such configuration that the obstruction is reduced to a minimum. Any backing, whirling and local frosting are avoided, since the flowing air nowhere strikes large iiat faces. The bars I4 and I4', even if not streamlined, are very narrow, and the brackets 2l are out of the Way. By these means, the efficiency of the cooler is much in- `creased, trouble is eliminated, and the power demand is reduced. t

Referring now to Figs. '7 and 8, this element has the two parallel flat walls 8 .and 9 as described, and its upper and lower sides are supported, in the example illustrated, by bars I4' of channel section, as shown in Fig. 6, but obviously bars such as illustrated in Figs. 4 and 5, with or without the brackets 2|, might be provided instead.

The welded-in baffles I3 described with reference to Figs. 1 to 4 are replaced by depressed ribs I8 in the plates 8 and 9 which are pitched at equal distance from each other, and project inwardly for half the depth of the element. By these means, as will appear from Fig. 8, each Itwo mating ribs make up a baffle. The inner sides of the ribs may be connected by any suitable means such as welded spots 38. The baffles I8 are arranged like the baflles I3, and the flow from pipe 6 to pipe 'I is indicated by arrows Il, as in Fig. 1.

It will appear that the element illustrated in Figs. '7 and 8 is as easily manufactured on a quantity production basis as the elements previously described.

It is understood that I am not limited to welding as the process of connecting the plates 8 and 9 of the elements, the baiiies I3 and the depressed ribs I8 but that the plates may be connected byv riveting, soldering, or in any other suitable manner.

Any number of elements I may be combined into cooling units, as described, and any number of such units may be connected in parallel or in series as required for a desired performance. The

asings of the individual units may be placed against a wall, as shown in Fig. 3, like a cabinet.

I claim:

1. In an air cooler, a cooling unit, fiat cooling elements each comprising a pair of parallel iiat walls, arranged in said unit to dene air ducts by the outer surfaces of their parallel fiat walls, means for circulating a refrigerant throughA said cooling elements at such a temperature that the outer surfaces of said walls are maintained at a temperature below zero, baiiies within each element for conducting the refrigerant through the element in a zig-zag path, a pair of welds connecting the upper and'- lower edges at one side of each baille to the adjacent element Wall, a llet in the other velement wall vfor connecting it to the other side of the baiiie, and means for establishing a flow of air through said air ducts at comparatively high velocity.

2. In an air cooler, a cooling unit, at cooling elements each comprising a pair of parallel at walls, arranged in said unit to dene air ducts by the outer surfaces of their parallel flat walls, means for circulating a refrigerant through said cooling elements at such a temperature that the outer surfaces of said walls are maintained at a temperature below zero, means for establishing a iiow of air through said air ducts at comparatively high velocity, and bars extending through said unit for holding said elements.

3. In an air cooler, a cooling unit, fiat cooling elements each comprising a pair of parallel flat Walls, arranged in said unit to define air ducts ing a flow of air through said air ducts at com-` paratively high velocity, bars extending through said unit for holding said elements, and brackets on said elements for engaging said bars.

4. In an air cooler, a cooling unit, fiat elements each comprising a. pair of parallel flat walls, arranged in said unit to dene air ducts by the outer surfaces of their parallel fiat walls, means for circulating a refrigerant through said cooling elements at such a temperature that the outer surfaces of said walls are maintained at a temperature below zero, means for establishing a iiow of air through said air ducts at comparatively high velocity, bars extending through said unit for holding said elements, and brackets on saldelements for engaging said bars, said brackets being arranged at the outer regions of the ow of the air.

5. In an air cooler, a cooling unit, at cooling elements each comprising a pair of parallel at walls, arranged in said unit to dene air ducts by the outer surfaces of their parallel fiat walls, means for circulating refrigerant through said cooling elements at such a temperature that the outer surfaces of said walls are maintained at a l.

temperature below zero, means for establishing a ymeans for circulating a refrigerant through said' cooling elements at such a temperature that the outer surfaces of said walls are maintained at a temperature below zero, means for establishing a flow of air through said air ducts at comparatively high velocity, and Ibars of channel section extending through said unit for holding said elements.

RICHARD WENZL. 

